Treatment of hydrocarbons



May 11) 1943 G, EGLOFF 2,318,765.

TREATMENT 0F HYDROCARBONS Filed Junev 1o, '1940 HYDRO GEA! AND `50 l ATALYST CONDENSER A l Alla/Aram 57 Z5.9

JWAcT/NATOR J3 coozEE l@ Patented May 11, 1943 TREATMENT F HYDROCARBONS Gustav Eglofi, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application June 10, 1940, Serial No. 339,675 Claims. (Cl. 19d-10) This invention relates to the simultaneous treatment of paraflln gases and a hydrocarbon oil to produce therefrom substantial yields of motor fuel of high antiknock value.

The process is particularly applicable to the treatment of paraln gases containing 2-4 carbon atoms per molecule together with gas oil distillates and naphthas produced as intermediates in the distillation of crude petroleum oils, but it may be applied also to the simultaneoustreatment of par'afn gases and distillates produced in the distillation of coal and of other hydrocarbonaceous oils produced by any means.

More particularly the process of this invention is concerned with the conversion of the aforementioned gaseous and liquid hydrocarbons under closely regulated conditions of operation conducive to the formation 'of high yields of motor fuel of good antiknock value.

In one specific embodiment th present invention relates to a process for produoinghigh quality motor fuels which comprises cracking a hydrocarbon oil in the presence of aluminum chloride to form a substantial yield of isobutane, producing normally gaseous olens from corresponding paraiiins by thermal decomposition and/or ,catalytic dehydrogenation reactions, and alkylating said isobutane by said normally gaseous olefins to produce a substantially saturated alkylate of high antiknock value. v

Substantial yields of isobutane may be obtained by heating hydrocarbon oils and hydrocarbon distillates in the presence of substantially anhydrous aluminum chloride, preferably in the presence of minor amounts of hydrogen chloride, using a relatively high reux ratio, correspondinglyflow rates of distillation, and vapor temperatures at the outlet of the still of the order of G-200 F. and preferably within the lower range. In some instances it may be preferable to add another metal halide to the aluminum chloride catalyst. 'I'he added metal halide may, for example, comprise a chloride of zirconium, zinc, iron, etc., which is relatively less active than aluminum chloride.

Normally gaseous parafiins as ethane, propane, and the butanes, either in admixture or individually, may be converted into substantial yields of gaseous olefins by thermal and/or catalytic methods. Pyrolysis or thermal conversion of the paraflinic gases'into olenic hydrocarbons may be eiected at a temperature in the neighborhood of 12001400 F. and undera pressure of from substantially atmospheric to approximately 100 pounds per square inch. f Olenic hydrocarbons may be formed from the gaseous parafns by dehydrogenation in the presence of a suitable catalyst at a somewhat lower temperature generallyv in the approximate vrange of 8001200 F. Suitable dehydrogenating catalysts may comprise composites. of refractory carriers and oxides of elements selected from the members of the lefthand columns of groups IV, V, and VI of the periodic table. The products from pyrolysis or dehydrogenation ofthe aforementioned gaseous parailins may be cooled to separate a gaseous fraction containing both parafns and-olefins from relatively minor amounts of liquid hydrocarbons which may arise lduring the thermal treatment.

Isobutane formed by aluminum chloride cracking and the paraiiln-olein mixture formed from the paraln gases may be commingled and fractionated vto remove a light fraction comprising essentially hydrogen and methane. The remaining mixture of 2-4 carbon atom hydrocarbons containing both olefins and isobutane may then be subjected to alkylation in the presence of a catalyst such as sulfuric acid, hydrogen fluoride. boron iiuoride with hydrogen fluoride or with uorine, or aluminum chloride with hydrogen chloride, generally at a temperature in the approximate range of -15 to 200 F. and under sufiicient pressure to keep in liquid phase a substantial proportion of the reacting hydrocarbons. Alkylation may be eii'ected also in the presence of a calcined composite of an acid of phosphorus and a generally siliceous adsorbent at a temperature in the approximate range of G-900 F. under a pressure of the order of 1000-3000 pounds per square inch. n

These alkylating catalysts which may beused alternatively are not necessarily equivalent in their action and the exact operating conditions to be used in their presence are dependent upon their activities, the composition of the hydrocarbon mixture, and other factors.

The accompanying diagrammatic drawing illustrates one specic form of apparatus in which the process of the invention may be conducted:

Referring to the drawing. a mixture of a hydrocarbon oil and aluminum chloride (which is ordinarily less than 20% by weight .of the charge) may be introduced through line I and valve 2 to pump 3 vwhich discharges through line 4 and valve 5 to coil 6 disposed to receive heat from furnace 1. The heated mixture of oil and aluminum chloride may be discharged from coil 6 through line 8 and valve S to fractionator III of adequate design for separating a hydrogenmethane fraction. isobutane, gasoline, and a higher boiling residue. Hydrogen and methane may be released from fractionator I through line Il containing valve I2. Isobutane separated from other products as hereinabove set forth may be withdrawn from fracti nator I0 through line I3 containing alve I4 and ,therein conducted to further treatment as hereinafter described.

.Gasoline separated in fractionator I8 may be withdrawn therefrom through line I5 containing valve I6 to cooler I1 and thence through n.1- down line I8 and valve I9 to storage, while a residue of higher boiling materials may be discharged from fractionator Ill through line 20 and valve 2|, the former, if desired, provided with a cooler, not shown.

A fraction comprising essentially paralnic hydrocarbons with 2-4 carbon atoms per molecule may be admitted through line 22 and valve 28 to compressor 24 which discharges through line 25 and valve 28 to coil 21 disposed to receive heat from furnace 28. Heating coil 21 may be subjected to a temperature of the order of 1200-1400 F. in order to effect substantial conversion of paraffin gases to oleflnic hydrocarbons. Heated products contained in coil 21 may be conducted therefrom through line 29 and valve 38 to cooler 3l and thencethrough run-down line 32 and valve 33 and receiver 34 in which may be collected hydrocarbons of gasoline boiling range formed during pyrolysis of the gaseous paraflin fraction. Receiver 34 is provided with a liquid draw-oil line 35 containing valve 36. If desired, allor a part of the pyrolysis products passing through run-down line 82 may be conducted therefrom through line 31 and valve '38 to fractionator 39 to which isobutane may be admitted through line I3, already mentioned. Gaseous products which may accumulate in receiver 34 may be withdrawn therefrom through line 48 and valve 4l to line 31, already mentioned.

If desired, isobutane from an outside source may be introduced through line 42 and valve 43 to pump or compressor 44 which discharges through line 45 and valve 46 to line I3, already mentioned, through which an isobutane fraction may be conducted to near the top of fractionator 39 thereby assisting in controlling the temperatures therein and aiding in separating a hydrogen-methane fraction from higher boiling gaseous products containing isobutane and oleiins. Fractionator 39 may comprise a distilling column of adequate dimensions for separating a Vfraction comprising essentially hydrogen and methane which may be discharged therefrom through line 41 and valve 48.

Alternatively the fraction comprising essentially paraffins with 2-4 carbon atoms per molecule may be converted into a substantial proportion of oleflns by contact with a dehydrogenating catalyst at a temperature in the approximate range of 8001200 F. This treatment may be carried out by disposing a granular dehydrogenating catalyst within heating coil 421 or in another suitable reactor provided with means for heating to the required temperature.

` Dehydrogenation may also be carried out by preheatlng the parafiln gas, as already described,

, in heating coil 21 and then admitting the heated gas to a reactor, not shown, containing granular dehydrogenating catalyst such as a composite o! activated alumina with chromium sesquloxide. As a further alternative a nely divided dehydrogenatlng catalyst may be mixed with the parailln gas fraction and conducted through a suitable heating coil. With the latter type oi' operation, means, not shown, will be provided for separating used powdered catalyst from the mixture of dehydrogenation products and unconverted lparailins which is thence conducted to fractionator 38, already mentioned.

From fractionator 39 a hydrocarbon mixture alkylator 5I may also be provided with a stirrer or other means of agitation.

In case a granular xed catalyst is employed such as a calcined composite of an acid of phosphorus and a generally siliceous adsorbent, the alkylator may be a cylindrical reactor designed to operate under the necessary conditions of temperature and pressure.

'I'he exact conditions of temperature and pressure used in any given alkylation will be determined by the catalyst employed, the composition of the reaction mixture, and by other factors.

.During the reaction, alkylation products and unconverted isobutane are Withdrawn from alkylator 5I through line 52 and valve 53 by lpump 54 which discharges through line 55 and valve 56 to fractionator 51 in which unconverted isobutane may be separated from the alkylation products and may lbe withdrawn through line 58 and valve 59 to cooler 60 and thence through rundown line6l and valve 62 to receiver 53 provided with gas release line 64 containing valve 85. From receiver 63 condensate comprising essentially unconverted isobutane may be withdrawn through line 6B and valve 61 by pump 68 discharging through line 69 and valve 10 into line 49, already mentioned, through which the fraction containing isobutane and olens is conducted to alkyla- Vremoval of unconverted isobutane in fractionator 51 a substantially saturated alkylate of high octane number may be withdrawn through line 18 and valve 19 to storage or tor distillation, not shown, to separate fractions of desired boiling range. l

It is generally preferable to add a small proportion of a hydrogen halide to the mixture of hydrocarbon oil and aluminum chloride being conducted to cracking to produce isobutane. It may also be advantageous to introduce a hydrogen-containing gas with the hydrocarbons charged to cracking as well as to alkylation. This may be accomplished, by means not shown, but apparent to one skilled in the art, utilizing a portion of the hydrogen-methane fraction formed in the process, particularly that available from the products of paraffin pyrolysis or dehydrogenation.

The results obtainable by these various alternative types of operation are not necessarily equivalent since the results obtained are generally dependen-t upon the materials charged, the

attraper particular catalyst employed, the conditions of operation, and other factors.

The following specic example is introduced to show results normally obtainable in the operation of the process, although with no intention of unduly limiting the -broad scope ofthe invention.

A California gas oil admixed with approximately 15% by weight of granular anhydrous aluminum chloride and 1% by weight of anhydrous hydrogen chloride may be conducted through a tubular heater maintained at about 600 F. to a fractionator in which the top temperature may be kept at approximately 100 F. Products obtainable from this step comprise approximately 25% by volume of liquid isobutane and 43% by volume of saturated aviation gasoline with 81 octane number. 'I'he isobutane may be commingled with an oleiln-containing fraction formed by pyrolyzing a propane-butane fraction at approximately 1300`F. under a pressure of 100 pounds per square inch. 'Ihe commingled mixture containing approximately 4 molecular proportions of isobutane per molecular proportion` of olenic hydrocarbon may be contacted at 45 F. with sulfuric acid of 98% concentration to produce a substantially saturated alkylate of 92 octane number.

products from said dehydrogenation 'with said liquid isobutane fraction under conditions suitable tor producing a liquid mixture comprising the liquid isobutane and said normally gaseous oleiins and subiecting said mixture to alkyiation to alhlate the isobutane with said normally gaseous olefins.

2. 'I'he process of claim 1 further characterized in that the dehydrogenation step comprises thermal dehydrogenation.

3. The process oi.' claim 1 further characterized in that the dehydrogenation step comprises catalytic dehydrogenation.

4.y A process for the production of high octane rating gasolinewhich comprises cracking a hydrocarbon oil' in the presence of aluminum chioride to produce isobutane, fractionating the cracked products to separate a liquid isobutane fraction, simultaneously and concurrently subjecting normally gaseous parafns to dehydrogenation to produce a substantial yield of normally gaseous olefins, scrubbing the conversion products from said dehydrogenation with said liquid isobutane fraction under conditions suitable for producing a liquid mixture comprising the liquid isobutane and said normally gaseous olefins and subjecting I'he character of the present invention and its noveltyand utility in producing gasoline from parailin gases and hydrocarbon oils containing substantially no gasoline can be seen from the preceding specification and example given, although neither section is intended to limit unduly its generally broad scope.

I claim as my invention:

1. A process for the production of high octane rating gasoline which comprises cracking a. hydrocarbon oil to produce isobutane, .fractionating the'cracked products to separate a liquid isobutane fraction, simultaneously and concurrently subjecting normally -gaseous paraillns to -dehydrogenation to produce a substantial yield of normally` gaseous oleiins, scrubbing the conversion said mixture to yalkylation to alkylate the isobutane with said normally gaseous olefins.

5. A process for producing antiknock motor fuel which comprises subjecting hydrocarbons to conversion to produce isobutane therefrom, fractionating the resultant products to separate a liquid isobutane fraction therefrom, simultaneously subjecting normally gaseous parafiins to dehydrogenation to convert a substantial portion thereof into normally gaseous oleilns, fractionating the gaseous products ofthe dehydrogenation in countercurrent contact with said liquid isobutane fraction and under conditions to form a liquid mixture of isobutane and normally gaseous olens, and subjecting said mix-ture to alkylation to react normally gaseous oleilns with isobutane.

' GUSTAV EGLOFF. 

